Ellroy was born in Los Angeles, California. His mother, Geneva Odelia (nee Hilliker), was a nurse, and his father, Armand, was an accountant and a onetime business manager of Rita Hayworth. After his parents' divorce, Ellroy relocated to El Monte, California with his mother. When Ellroy was ten years old, his mother was murdered. The police never found the perpetrator, and the case remains unsolved. The murder, along with reading The Badge by Jack Webb (a book composed of sensational cases from the files of the Los Angeles Police Department, a birthday gift from his father), was an important event of Ellroy's youth.